Conventional cable networks have long been used to distribute content over physical communication media such as coaxial cables, fiber optic links, etc., to multiple subscribers. Typical distribution of content includes modulating a signal in accordance with QAM (Quadrature Amplitude Modulation) encoding and then transmitting the modulated QAM signal to multiple subscribers over the physical communication medium. Typically, the signals transmitted over the physical communication media are encoded at RF (Radio Frequency) oscillation rates.
There is currently is no interference mitigation technique built into cable network plants to compensate for interference caused by wireless network signals such as those associated with LTE (Long Terminate Evolution) networks. In general, LTE is a wireless network that operates in the same frequency bands as many cable operators. For example, the majority of LTE deployments in the United States are currently taking place in two Frequency bands such as band 13 (DL 746-756 MHz, UL 777-787 MHz) for Verizon™ and Band 17 (DL 734-746 MHz, UL 704-716 MHz) for AT&T™, both of which are within operating frequencies used by the cable operators.
Propagation and attenuation characteristics of wireless 700 MHz signals are very different from wireless signals at higher frequencies. For example, these relatively lower frequency signals travel further and are less attenuated by structures, etc., than higher frequency wireless signals. Thus, presence of such signals in an environment can have a greater interference impact to other devices.
Additionally, wireless base stations such as so-called picocells that transmit around this frequency range (e.g., 700-800 MHz) may be deployed in close proximity to a respective cable network plant, increasing a likelihood of possible interference with signals transmitted in a coaxial cable.
It is further noted that LTE technology uses so-called Orthogonal Frequency-Division Multiplexing (OFDM) in a respective downlink. This means LTE signals also have a higher peak-to-average radio (crest factor) than other cellular technologies. Generally speaking, a signal with a higher crest factor will lead to more ingress interference as the signal energy is concentrated in a smaller portion of the allocated bandwidth. Especially in the case of an LTE uplink, it is highly unlikely that all resource blocks will be allocated at the same time.